XR16C2850
xr
2.97V TO 5.5V DUAL UART WITH 128-BYTE FIFOS
REV. 2.1.3
22
TABLE 8: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1
ADDRESS
A2-A0
REG
NAME
READ/
WRITE
BIT-7
BIT-6
BIT-5
BIT-4
BIT-3
BIT-2
BIT-1
BIT-0
COMMENT
16C550 Compatible Registers
0 0 0
RHR
RD
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
LCR[7] = 0
0 0 0
THR
WR
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
0 0 1
IER
RD/WR
0/
Modem
Status Int.
Enable
RX Line
Status-
Int.
Enable
TX
Empty
Int.
Enable
RX
Data
Int.
Enable
CTS#
Int.
Enable
RTS#
Int.
Enable
Xoff Int..
Enable
Sleep
Mode
Enable
0 1 0
ISR
RD
FIFOs
Enabled
FIFOs
Enabled
0/
INT
Source
Bit-3
INT
Source
Bit-2
INT
Source
Bit-1
INT
Source
Bit-0
INT
Source
Bit-5
INT
Source
Bit-4
0 1 0
FCR
WR
RXFIFO
Trigger
RXFIFO
Trigger
0/
DMA
Mode
Enable
TX
FIFO
Reset
RX
FIFO
Reset
FIFOs
Enable
TXFIFO
Trigger
TXFIFO
Trigger
0 1 1
LCR
RD/WR Divisor
Enable
Set TX
Break
Set
Parity
Even
Parity
Enable
Stop
Bits
Word
Length
Bit-1
Word
Length
Bit-0
1 0 0
MCR
RD/WR
0/
Internal
Lopback
Enable
OP2#/INT
Output
Enable
Rsvd
(OP1#)
RTS#
Output
Control
DTR#
Output
Control
LCR[7] = 0
BRG
Pres-
caler
IR Mode
ENable
XonAny
1 0 1
LSR
RD
RX FIFO
Global
Error
THR &
TSR
Empty
THR
Empty
RX
Break
RX Fram-
ing Error
RX
Parity
Error
RX
Over-
run
Error
RX
Data
Ready
1 1 0
MSR
RD
CD#
Input
RI#
Input
DSR#
Input
CTS#
Input
Delta
CD#
Delta
RI#
Delta
DSR#
Delta
CTS#
1 1 1
SPR
RD/WR
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
LCR[7] = 0
FCTR[6]=0
1 1 1
EMSR
WR
Rsvd
Auto
RTS
Hyst.
bit-3
Auto
RTS
Hyst.
bit-2
Rsvd
Rx/Tx
FIFO
Count
Rx/Tx
FIFO
Count
LCR[7] = 0
FCTR[6]=1
1 1 1
FLVL
RD
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
Baud Rate Generator Divisor
0 0 0
DLL
RD/WR
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
LCR[7] = 1
LCR
≠ 0xBF
0 0 1
DLM
RD/WR
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0